In 2007, the authors published an article on interventions in aseptic processing to bring attention to the contamination risk associated with human workers in cleanrooms (1). The authors made the salient point that interventions are associated with contamination risk and should be avoided. In fact, as the authors previously suggested, no intervention is safe or risk-free, and the perfect intervention is the one that isn't necessary. Interventions should be avoided at all times because each one exposes the product, and ultimately the patient, to increased risk.

The authors' original effort was concise and sorely needed at the time, but hindsight reveals that it was incomplete. This article reflects the authors' recognition that more needs to be said about this important subject. As consultants, the authors are in almost daily conversations about aseptic processing, and interventions often are directly or indirectly central to the topic of discussion. For example, discussions regarding environmental-monitoring issues often relate to personnel and interventions just as those about media-fill contamination or product-testing issues do.

The current article does not reflect a change in the authors' original position with respect to interventions. It is, rather, an attempt to clarify how that position should be understood within the industry. The authors also will elucidate how interventions should be defined and managed. The authors hope that this expanded discussion leads to a pragmatic consideration of risk assessment and management, hence more efficient and effective quality-improvement programs, as well as better standard-setting and regulation.

Inherent and corrective interventions

The authors' first effort defined interventions as either routine or nonroutine. The intervening years have provided reason to establish more definitive categories than before. Two major categories still are appropriate, but they should be defined somewhat differently. The previous paper stated that routine interventions were predominantly inherent and that nonroutine interventions were largely corrective. The distinction appeared to be sufficiently clear, but were chagrined to find that some individuals and firms misunderstood or ignored the distinction. For example, at least one particular corrective intervention was considered routine because it had to be performed frequently during the execution of a batch.* This interpretation violates the principle that no intervention is safe, and it is disturbing to note that an intervention was tolerated as an acceptable activity largely because of the frequency with which it had to be performed. This misinterpretation denies the very concern that the authors wished to highlight: that interventions are inherently risky and the goal should be to reduce their number. To dispel confusion, this article will restate the author's perspectives with respect to interventions in aseptic processing. Also, the benign acceptance of frequent mechanical problems or component feed difficulties is cause for concern. Experience has taught us that interventions that produce line stoppages are avoidable. Under continuous process improvement, ongoing efficiency problems should be resolved for commercial as well as contamination-risk reasons.